The present invention relates to an arrangement for gasifying fuels. More particularly, it relates to an arrangement for gasifying fuels within the range from fine grain to dust-like fuels in a dust cloud with oxygen and/or air and in some cases water steam in a gasifying reactor which is provided with at least two burners located in a plane in the side wall of the reactor.
The autothermal gasification of the fine grain-dust-like fuels with an average grain size from approximately 50 um in the dust cloud with oxygen and/or air and in some cases with water steam has been known for a long time under the name Koppers-Totzek process. In accordance with this process a fuel to be gasified and the reaction medium are blown through the burner into an empty gasification reactor and converted there into a crude gas by partial oxidation and temperatures above the slag melting point. The crude gas can be processed to synthetic gas or fuel gas. When this process is performed under normal pressure, the fuel can be supplied to the burners through a screw conveyor which allows a sufficient quantity regulation. The fuel is first supplied by the screw conveyor first to a so-called mixing head, and from there it is blown by the stream of the gaseous or vaporous reaction media through the burner head into the gasification reactor. More recently there has been a tendency to develop this process further so that the gasification can be performed with increased pressure between 10 and 100 bar, preferably between 25 and 45 bar. The pressure version of the Kopper-Totzek process is identified as PRENFLO process. In this case the screw conveyor is hardly suitable for the transportation of the fuel to the burners. Instead, a pneumatic conveyance with preferably inert conveying gas is utilized.
The gasification in the dust cloud requires an exact arrangement of the fuel and reaction medium. Gasification reactors with high throughput are provided for example with two or more burners. For an optimal operational result, a fuel supply of a uniform quantity and uniform shape must be provided to all burners of the gasification reactor. In normal case the deviation region of the supply stream density during the fuel supply must be only approximately .+-.2%.
For solving this problem it has been proposed in the German document No. DE-OS 3,509,221 to connect each pair of the burners of a gasification reactor with a common fuel supply device by symmetrically arranged conduits. This solution requires satisfying certain symmetry requirements with respect to the positioning of the fuel supply device and the conduit path to the gasification reactor. With two or more gasification burners also additional fuel supply devices are required in this case. These requirements lead to respective investment and operation costs and do not provide an optimal solution of the above mentioned problem.